1. Field of the Invention
The present invention relates to a carrier vehicle.
2. Description of the Related Art
The carrier vehicle is an operation vehicle for loading and carrying a load loaded and unloaded by a fork lift above a load carrying platform, or loading and carrying soil or rock loaded by a wheel loader or a hydraulic excavator above an inclinable load carrying platform.
FIG. 3 is an outline side view showing a power train of an off road type dump truck which is a carrier vehicle. As shown by FIG. 3, an off road type dump truck having a dump vessel 38 inclined by a hydraulic cylinder, not illustrated, at an upper portion thereof is mounted with front wheels 35F at steerable front axles 34F respectively provided on left and right sides of a front portion of the vehicle and mounted with rear wheels 35R at both left and right ends of a rear axle 34R provided at a rear portion of the vehicle. A power train of the dump truck subjects an output or an engine 31 provided at the front portion of the vehicle to speed change by a transmission 32 mounted at a middle portion of the vehicle and the rear wheels 35R are driven by transmitting the output of the engine 31 from the transmission 32 to the rear axle 34R via a propeller shaft 33.
However, according to the above-described related art, a problem described below is posed.
That is, although it is conceivable to promote large-sized formation of a carrier vehicle to achieve promotion of operability at a large-scale operation site, in this case, in accordance with fabrication of the large-sized carrier vehicle, not only the engine 31 to which large power is requested but also respective components constituting the power train of the transmission 32, the propeller shaft 33 and tires become large-sized and special. Therefore, production facilities and productivity of the respective components constituting the power train become problematic and cost of the power train becomes very high.
The invention has been carried out by paying attention to the above-described problem and it is an object thereof to provide a carrier vehicle capable of restraining an increase in cost of a power train in accordance with large-sized formation of the vehicle.
In order to achieve the above-described object, a carrier vehicle is constructed by a constitution including front axles provided respectively steerably on left and right sides of a front portion of the vehicle and mounted with wheels, a first engine provided at the front portion of the vehicle, a first drive axle provide data middle portion of the vehicle and mounted with wheels at both left and right ends thereof, a first transmission provided to connect to a rear side of the first engine for transmitting a drive force of the first engine to the first drive axle, a second drive axle provided at a rear portion of the vehicle and mounted with wheels at both left, and right ends thereof, a second engine provided at the rear portion of the vehicle and on an upper side of the second drive axle, and a second transmission provided to connect to a front side of the second engine for transmitting a drive force of the second engine to the second drive axle via a transfer.
According to the above-described constitution, the drive axles are provided at the middle portion and the rear portion of the vehicle and driven by the power trains separate from each other and therefore, an output necessary for each of the power trains becomes as small as, for example, substantially a half of an output necessary for the carrier vehicle. Therefore, even when a large-sized carrier vehicle is fabricated, each of components (engine, transmission and the like) constituting the power train becomes comparatively small-sized in accordance with an output necessary for each of the power trains.
The cost of a complicated and fine component of the engine or the transmission becomes very high owing to problems of production facilities and productivity when a large-sized component is fabricated. However, according to the invention, even when a carrier vehicle is large-sized, a power train including an engine and a transmission does not become large-sized and special in correspondence with large output but each of components of the power train becomes comparatively small-sized and therefore, large-sized formation of the component is prevented, an increase in the cost can significantly be restrained and a large-sized carrier vehicle at low cost can be provided.